Videoconferencing Debuts on the Internet

February 28, 1995

By Jeffery Kahn, JBKahn@LBL.gov

BERKELEY -- In March 1992, a new venue quietly debuted on the Internet -- one
in which people worldwide could meet in a common electronic window and not only
see and talk to one another, but work on a shared "whiteboard." This
conferencing network -- called the Multicast Backbone, or MBone -- has the
potential to launch a new era in scientific collaboration.

"Among scientists," predicts Stewart Loken, "MBone conferencing will become as
routine as e-mail. And, it will happen much sooner than you think."

Loken, a pioneer in the use of videoconferencing, oversees LBL researchers who
have played a prominent role in creating the MBone. Having invented most of
the tools used during an MBone conference, LBL researchers most recently helped
create new protocols that soon should make the MBone accessible to anybody with
an Internet-linked workstation.

Today, the MBone is the fastest growing component of the Internet. Since its
inception, MBone conferencing has grown exponentially with traffic doubling
about every eight months. Right now, more than 10,000 people in 30 countries
are using it for collaborative work.

Despite its explosive growth, the MBone has been difficult to access with most
of its usage by computer scientists and engineers doing network research. This
is because the routers that direct traffic around the Internet are unable to
deal with multicast (MBone) addressing. Consequently, local and regional
networks have had to be jury-rigged to patch individuals to an MBone session.
New router software is coming onto the market that will automate the MBone.
Anyone on the Internet will be able to conference with everyone else on the
Internet.

LBL's Van Jacobson is one of the three principal creators of MBone. The others
are Steve Deering, of Xerox Corp.'s Palo Alto Research Center, and Steve Casner
of the University of Southern California. Deering and Casner developed the
multicasting protocols that made the virtual network possible, and Jacobson
created many of the tools that make it valuable.

In multicasting, rather than send information to a single location, the
network distributes it from senders to every receiver who has signed up for the
session. Because MBone usually includes live video, which means huge volumes of
traffic, efficiency was a prerequisite to prevent congestion and collapse of
the Internet. The software underlying MBone dynamically finds the shortest,
most efficient paths, sending a single copy of a video conference onto the
network, and replicating it only where there is a split in the path leading to
individual participants.

MBone was first used to simulcast the March 1992 Internet Engineering Task
Force conference. Since then, it has provided around-the-clock coverage of
space shuttle flights, an opportunity for doctors in England and Sweden to
observe and question a surgeon in San Francisco performing a complex liver
operation, and a place for Ph.D. candidates to defend their dissertations to
committee members.

"The tools are so easy to use that anybody can announce a session and be their
own producer," Jacobson says. "Somebody actually sent out to the universe live
pictures of their pet iguana climbing a tree."

MBone offers a number of advantages over traditional teleconferencing, which
joins together only those rooms specifically wired for videoconferencing.
MBone joins all those who have a workstation with audio/video capabilities and
a high-speed Internet connection. This ability to connect many more individual
offices has resulted in moves by both the Department of Energy and NASA to
replace teleconferencing with MBone meetings.

Jacobson's research group at LBL includes Steve McCanne and Sally Floyd.
Jacobson and McCanne designed the whiteboard, which Jacobson calls an "infinite
piece of paper." It allows participants in an MBone session to write, type, and
draw on a shared drawing window. It even has a memory, so that those using it
can flip pages, scrolling back to earlier versions of the contents, or import
other drawings and text.

Jacobson also developed the session directory, a conference coordination tool
that provides a menu of what is currently available or upcoming on MBone. The
Session Directory allows the user to join a session, or to announce and
advertise an upcoming session.

The tool pack developed by Jacobson's group also includes VIC (Video
Conferencing) and VAT (Visual Audio Tool). These make it possible for all
parties to both talk and listen. It also makes possible the transmission of a
video stream to an unlimited number of participants.

Most recently, Jacobson was part of the team that developed the Protocol
Independent Multicast software upon which the next generation of routers will
be based. Thanks to Jacobson, Deering, and researchers from the University of
Southern California and Cisco Systems, multicasting will now be a basic feature
of routers. With this change, the labor-intensive patching required to hookup
to an MBone conference will be eliminated. This means that the MBone now will
become an integral and invisible part of the Internet.

Says Loken, "I believe that 1995 will be to MBone what 1994 was to the World
Wide Web. Almost unknown right now, Internet videoconferencing is about to
become commonplace."

LBL is a national laboratory that conducts unclassified scientific research
for the U.S. Department of Energy. It is located in Berkeley, California, and
is managed by the University of California.